PB1988: AL CARDIAC AMYLOIDOSIS: A CASE SERIES OF 13 PATIENTS AND LITERATURE REVIEW
Authors: S. Chadli, M. Maamar, H. Khibri, S. Belkhettab, N. Moatassim, W. Ammouri, H. Harmouche, Z. Tazi Mezalek
Journal: HemaSphere (2022)

Background: Amyloidosis is a systemic disease caused by the extracellular deposition of misfolded proteins in various tissues and organs. Cardiac involvement is commonly observed and has a major impact on prognosis. The light chain immunoglobulin is the most severe subtype involved, associated to a poor outcome. Aims: The objective of our study is to describe the clinical profile and outcome of patients with AL cardiac amyloidosis, and compare our results to the literature. Methods: We retrospectively conducted a monocentric and descriptive study, including the medical records of 56 patients admitted in our department for a systemic amyloidosis, between 2015 and 2022. A cardiac involvement was confirmed among 18 patients. 13 cases of AL cardiac amyloidosis were enrolled. Results: Patients were mostly males with a sex ratio (M/F) of 2.2, and a mean age of 59 ± 13 years. Two patients were previously diagnosed with a multiple myeloma, one patient had a T lymphoma in complete remission, and one patient had a monoclonal gammapathy of undetermined significance. Patients symptomatology consisted mostly in dyspnea and peripheral edema (54%), with a mean duration of 12 ± 4 months. On cardiovascular examination, signs of right and global heart failure were found in respectively 50% and 15% of the cases. Were observed simultaneously: mucocutaneous (46%), renal (30%), neurologic (30%), digestive (23%), articular (15%), muscular (15%), and ocular (8%) involvements. The main electric abnormalities were: low-voltage (38%), atrioventricular block (23%), and right bundle branch block with repolarization abnormalities (15%). On chest x-ray, a cardiomegaly was found in half of the cases. Transthoracic echocardiography revealed: left ventricular hypertrophy (100%), septal and valvular hypertrophy (70%), sparkling myocardium (60%), pericardial effusion (54%), bull’s eye strain pattern (46%), diastolic dysfunction (46%), dilated cavities (46%), pulmonary hypertension (23%), and intracardiac thrombosis (8%). Systolic function was generally conserved, with a mean of 50 ± 6 %. On cardiac MRI, the most frequent features were: left ventricular hypertrophy (100%), delayed myocardial enhancement (50%), and abnormalities in myocardium nulling (40%). Biological findings included a median troponin of 0.95 ng/ml [0,10; 67,12] and NT-proBNP of 5640 pg/ml [2577; 14 825]. Bence Jones proteinuria was positive in 30% of the cases. All patients presented a low plasma cell infiltration (4 to 8%), except one (25%). The (4;14) translocation was positive in one case. The monoclonal light chain involved was lambda (62%) and kappa (38%), with a median dFLC of 429 [34; 3053]. Patients were all put under chemotherapy: Daratumumab-Velcade-Cyclophosphamide-dexamethasone (30%), Velcade-Cyclophosphamide-dexamethasone (23%), Melphalan-dexaméthasone (23%), Cyclophosphamide-Thalidomide-dexamethasone (8%). A complete remission was obtained in one patient, and a partial remission in two patients. A death was recorded in six cases, following a cardiogenic shock (n=2) and arrhythmias (n=4). Summary/Conclusion: Cardiac AL amyloidosis is a life-threatening condition. Because of its rapid progression and nonspecific clinical features, it is often misdiagnosed or discovered lately during the disease course. The AL subtype is linked to a poor survival rate because of the frequent malignant nature of the underlying disease and the high cardiac toxicity of the monoclonal light chains. We thus believe that a screening of patients at risk to develop AL amyloidosis could lead to an early diagnosis and better prognosis.